This would not be the first time that an unexpected change in government back home puts diplomats at the U.N. in a delicate position: the Libyan ambassador and deputy ambassador defected before the government of the late Muammar Qaddafi fell. But sometimes, the ambassador is career foreign service and stays despite a change in government, as in the case of Egypt's Ambassador Mootaz Ahmadein Khalil.

Ukraine's U.N. ambassador, Yuriy Sergeyev, has been representing the country at the U.N. since 2007, and spent two decades in the foreign ministry, assigned at times in Kiev, at others as Ukraine's Ambassador to Greece and Albania; its ambassador to France; as the permanent representative of Ukraine to UNESCO; as well as in a minister role in Northern Ireland.

And Sergeyev is standing his ground, saying to reporters on Monday that, although he does not know the whereabouts of President Viktor Yanukovich, "We are here not to work for the government. We are here to work for the state and its people."

Sergeyev said that the protests in his country are not about accession to the European Union. At a U.N. press briefing, he said, "The people are fighting not for the European Union accession. No. This became secondary. They ran to the street to defend dignity and to defend their rights."

But by Wednesday, the ambassador was more adamant about the conflict in his country. He told CBS News, through his spokesman, Ehor Pivovarov, that "all attempts by Russia to destabilize the Crimean peninsula are a waste of time. Crimean populations, the Tartars ethnic minority in particular, are living under a constant threat by radical groups, sponsored by 'some' state."